1. Field of the Invention
The invention relates to an electromagnetic actuator used in conjunction with a fluid-flow regulating valve. More specifically, the invention relates to an electromagnetic actuator that will produce a substantially linear pressure output of a fluid regulating valve.
2. Description of the Related Art
Actuators are used to move devices, or elements thereof, between positions of operation. By way of example, an actuator may move a switch from an open condition to a closed condition. Actuators may also move elements between a plurality of positions. In the case where an actuator operates a valve, a valve may move between open and closed positions. In addition, the actuator may move the valve to a plurality of positions between the open and closed position to regulate the flow of material, i.e., fluid flow, as it passes through the valve by varying the size of the opening created within the valve.
When controlling the flow of fluid, it is important to control the pressure of the fluid as it flows through the valve. It is desired to operate the pressure control valves to minimize the pump flow by specifying zero flow at the minimum current condition and zero flow at the maximum current condition. These parameters create a flow curve that is bell-shaped in nature. In addition, a linear pressure curve is desired. In a linear pressure curve, the pressure may go from zero to a higher value in a normally closed condition, whereas it will go from a high value to zero in a normally open condition.
Typically, for pressure control valves, the magnetic force position curve is designed to be as flat as possible relative to the position of the valve such that the force varies only as a function of the current of the fluid flowing therebetween. For a valve with a bell-shaped flow curve, this is not a suitable solution because the resistance force to valve movement is not linear. The curve in the flow pressure leads to a lack of resolution and linearity of the pressure control curve valve, which is not desirable. Therefore, there is a need to design a solenoid valve that can regulate fluid flow by having a magnetic flow position curve that matches the flow resistance curves of the fluid. Such a design will achieve a balance throughout the available current domain and the balance is uniform.